I don't know ANYTHING about boxing, so bear with me. Why do they fight on such an infrequent basis? Does it take them a really long time to recover? Or, do they need that big gap of time to properly hype up the next fight? Someone please explain this to me.

There are a variety of reason. The biggest guys fight only every so often because of...money.

In this day and age, if someone gets a few losses, their earning power goes down. If a fighter doesn't fight for a while, and he is good and people want to see him, he'll make 15-30 million (like this past weekend's fight). If a fighter fights every month or two, then the PPVs have no "drama" or build-up.

Another reason is that there are so many promoters. Say you had "great fighter A" and I had "great fighter B," everyone bickers for months to get their...money.
Fighters want to be paid, setting up a venue, promotion, blah, blah, blah.

Supply and demand (and pay per view) basically. If a fighter fights so much, they all can't be pay per view or people won't buy them every week.

before you make a name for yourself, boxers fight many times per year, though this is against lesser competition. as they start to get known and become a draw, they cut down for financial reasons, build up and because more fights = more chances to lose.

Boxers start off having around 10 fights a year. And every fight thay have is ment to be a learning experience and to get there name known. As thay become well known thay cut it down to around 3-4 fights a year, this is mainly because thay dont need the money as much. Thay spend more time training before a big fight and competition gets smaller.

Another reason is to make the certain weight that they need to reach. Then, when reached they have to condition themselves in order to at least be somewhat "accustomed" to that weight class. Plus, they are greedy bastards.